Government controls on availability of physicians and hospital resources can counteract some undesired aggregate consequences of reimbursement insurance. Given aggregate controls, many important questions arise concerning nonprice rationing of services by physicians. A theoretical model of rationing should be consistent with existing items of evidence on delays, disequilibrium, and "availability effects." The model discussed in this paper has a foundation in the mutual advantages of a long-term association between an individual client and physician; these advantages motivate an implicit contract for rationing with a variety of testable implications.